Ever more stringent regulations with regard to admissible pollutant emissions of motor vehicles with internal combustion engines require the pollutant emissions during the operation of the internal combustion engine to be kept as low as possible. This may be realized firstly by reducing the pollutant emissions that arise during the combustion of the air/fuel mixture in the respective cylinders of the internal combustion engine. Secondly, in internal combustion engines, exhaust-gas after treatment systems may convert the pollutant emissions generated during the combustion process of the air/fuel mixture in the respective cylinders into benign substances. For this purpose, use is made of exhaust-gas catalytic converters which convert carbon monoxide, hydrocarbons and nitrogen oxides into benign substances.
Both the reduced generation of the pollutant emissions during the combustion in the respective cylinder and the conversion of the pollutant components with high efficiency by way of the exhaust-gas catalytic converter necessitate a very precisely set air/fuel ratio for the respective cylinder.
An intake pipe charging model is described for example in the specialist book “Handbuch Verbrennungsmotor, Grundlagen, Komponenten, Systeme, Perspektiven” [“Internal combustion engine compendium, principles, components, systems, perspectives”], 2nd improved edition, publisher Richard vanBasshuysen/Fred Schäfer, 2nd improved edition, June 2002, Friedrich Vieweg & Sohn Verlagsgesellschaft mbH, Braunschweig/Wiesbden, pages 557 to 559. Furthermore, intake pipe models of said type are also described in EP 0820559 B1 and EP 0886725 B1.